Grinding machine



H. E. HARRIS Aug. 12 1924.

GRINDING MACHINE Filed April 22. 1920 2 Sheets-Sheet 1 INVENTOR HARRY 1115111215 ATTORNEY Aug. 12, 1924. 1,504,556

H. E. HARRIS GRINDING MACHINE Filed April 22 1920 2 Sheeis5heet 2 INVENTOR HARRY E. HARRIS ATTORNEY Patented Aug. 12, 1924.

PATENT OFFICE.

HARRY E. HARRIS, BRIDGEPORT, CONNECTICUT.

GRINDING MACHINE.

Application filed April 22, 1920. Serial No. 375,659.

To all whom it may concern:

Be it known that HARRY E. HARRIs, a citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, has invented certain new and useful Improvements in Grinding Machines, of which the following is a speci fication.

This invention relates to precision machines, and has been devised more particu larly in connection with grinding machines though it should be recognized that many of the novel features may be utilized with great advantage in other relationships. a A serious problem which is met with in machines of this character is that of protecting the working tool from shocks and vibrations transmitted thereto through the tool actuating mechanism, even variations in a driving belt such, for example, as at the point of lacing, being sufficient if not properly provided for to produce noticeable imperfections in the work. Serious disturbing forces also arise at the working portion of the tool; 7 Y

This invention proy'ides novel means by which these problems have beensolved quite satisfactorily, an important element thereof being the employment of gyrostatic shock resisting means interposed between the tool and its driving mechanism and holding the tool to its work. For this purpose a heavy gyrostatic wheel is used tocarry the work ing tool, this wheel acting not only by the momentum of its rotation to operate uniformly notwithstanding sudden and severe changes in operative load, but also through its gyrostatic effect to prevent deviations from its normal rotating position, which not only in itself produces more perfect work but eliminates eccentric forces destructive to accuracy ofthe bearings. Furthermore .the mass of the tool being relatively small as compared to that of the wheel, it becomes a comparatively easy matter to adjust the parts in rotating balance, variations in the tool itself being of little consequence. This is of particular importance in grinding wheels it being commercially impractical to form abrasive wheels homogeneously enough to insure rotative balance.

Novel drive mechanism driving at both ends of the tool carrying shaft and including shock absorbing elements has also been provided as will presently be described.

An improved arrangement of bearings has been devised, together with guards for protecting them from the entry of cooling liquids or foreign matter, such as abrasive ma terial or the like, these guards being so 0011- structed as to form convenient engaging means for handling or hoisting devices in assembling or disassembling the machine.

A novel casing for the grinding wheel has also been provided, this casing carrying truing tools for the grinding wheel, readily adjustable relative thereto and independently actuated to true the wheel in an expeditious and satisfactory manner. These tools are so mounted as to act in planes substantially diametrically of the wheel to properly form and position its cutting surfaces.

A supplementary truing tool is also provided, by which, together with the tools carried by the casing, the configuration of the standard U. S. thread may be produced.

Other objects and advantageous details and combinations of parts will appear from a description of one embodiment of this invention disclosed in the accompanying drawings illustrating portions of a machine, constructed in accordance therewith,vfor grinding screw threads.

In these drawings,

Fig. 1 is an end elevation partly in section.

of a portion of the machine.

F g. 2 1s a partial front elevation partly in section of the same portion.

Fig. 3 is a section on line 33 of Fig. 1..

Fig. 4 is a somewhat diagrammatic View showing the relative arrangement of the wheel truing devices, and

Fig. 5 is a diagrammatic View illustrating the grinding wheel driving mechanism.

VA represents a portion of the machine frame formed at its top with inclined guide flanges for the slidable reception of a supporting block B formed on its upper surface with a curved lateral guideway, for the reception of a machine base C. Bolts as l and 2 pass through slotted flanges in the base C and into the block B for retaining the base 0 in any angular position desired with relation to the block'B. A turn buckle 3 pivoted at one end to the base C and at its other end to a lug extending from the.

block serves to adjust" the base C angularly with relation to the block B as desired.

Carried on the top face of the base C are four bearing blocks 4, 5, 6, and 7 in substantial alignment. The intermediate blocks 5 and 6 are formed to receive ballbearings for a main grinding wheel shaft 8 carrying between the'blocks' 5 and 6 and fixed to rotate or integral therewith a heavy wheel 9 havingan integral flange 10 anda ring 10 forming a flange spaced therefrom between whlch flanges is made fast the tool in 1 the fOIIH Of a thin .ring 11- of abrasive material. Shaft 8 together with the grinding Wheel is carefully adjusted for rotative balance as a unit; The ball-bearings supported byblocks 5 and 6 are identical in 'construcrings14 and 15 and collars 17 and 18 are the reception of a screw threaded retaining the blocks '4 and screwed into the open ends thereof and into COHt/EtCt' with the rings14 and 15. Guards in the form of rings l9 and 20 are carried on the shaft 8, external'to the rings 12 and 13 and haveoutwardly turned flanges close- 1y approaching the inner surfaces of the retaining rings 17 and 18 which are made fast in the casing 17 by suitable screws. The shaft 8 is shouldered as shown at 21 and between the shoulder and the ring 19 is a sleeve 22 having integral therewith a disc shaped guard portion 23 having perforations 23 therein. Each outer end por tion of the shaft 8 is screw threaded for ring 24 which may be tightened up; against the guard 20.

p In substantial alignment with the shaft 8 are a pairof shafts'25 and 26, journaled in 7 and carrying at their outer ends belt pulleys '27 and 28. At their inner ends these shafts carry flexiblecouplings 29 and30. As shown, each of these couplings consist of two discs of flexible material, such as leather or the like having interposed therebetween a ring of metal or other suitable material made fast by screws to both discs. The inner discof each flexible coupling carries one member of a jawed driving connection as 31, 32 arranged to co- OPGILtBWllZh mating members 33, 34 on the 7 adjacent ends of the shaft 8, screws 31, 32 being employed to reduce lost motio'n'to the i V extent de'sired.

Supported from a bracket extending rearwardly from the base rt at each side therof is pivotedat 35, a link 85, one'onl V of these linksfbeing shown. v Pivoted to link I icarrying at itsupper end a bearing 36 for u a st'ub'ior jack shaft carrying two belt pulis a vertically extending arm 36 ward pivotal motion formed as a forwardly leys 37, 38 mounted for rotation therewith. Belt pulley 37 is connected by a belt a to the pulley 28 and the pulley 38 is similarly connected by a belt 5 to a pulley 38 on an overhead shaft E as is shown iagrammat-ically in Fig. 5. An arm 39 extends rearwardly from thelower end of arm 36 forming a bell crank lever therewith, the outer end of this arm 39 supporting a weight V by means of the cable 40. Weight serves to tension the belts a and I), tending to draw down the arm 36 by rocking the link on its pivot 35', and drawing belt wheel 37 rearwardly about the pivot 36, to provide a resilient driving connection from shaft E. A similar drive connection is made from the pulley 27 to a belt pulley 41 identical with belt pulley 37 and also made fast to the overhead drive shaft E.

Carried by or integral with the blocks 5 and 6 is the lower portion of a grinding wheel casing and pivoted at the point 51 thereto is an upper casing portion 52 having forwardly extending spaced portions and 54 overlying the bearings carried by blocks 5 andf6. Locking bolts 55 and 56 pivoted to the lower casing member 50 in suitable slots therein-may be swung into position in slotted extremities of the portions 53 and 54 and made fast in such positions by means of thumb nuts 58 and 59, to fasten the u) )er casing portion 52 in closed position. ating perforations in portions 53 and 54 and the casings 16 may receive suitable lubricating cups for the bearings. Extending rearwardly from the base C is a bracket 60 which may be contacted by a portion 61 carriedbythe casing part 52 rearwardly of the pivot 51, to limit the rearward and upof portion 52 when the holding screws 55 and 56 have been released.

A sheet metal lower casing portion 62 surrounds the lower half of the guard discs 23 above described, and a similar upper guard member 63-surrounds the upper half thereof, and is made fast to a sheet metal wheel casing member 64 attached at its upper end by screws 65, 65 to the portion 52. The guard members 64 approach closely adjacent the outer faces of the grinder carrying wheel 9, being cut away at 66 to allow the presentation of work to the grinding edge, a center for holding the work thereto beingshown at 67 in Fig. 1.

The upper portion of the member 52 is and upwardly inclined bearing bracket 68, having a slideway 69 on its forward face surmounted by an overhanging flange 70. In the slideway 69 is a block 7l'hav-ing a lug 72 threaded for the reception of a screw 73 journaled in the flange 70. The upper end of screw 73 is provided with a knurled head 73 by which it may be turned.

Pivoted at 74:, in the plane of ring 11, to the block 71 are overlapping base flanges of a pair of posts 75 and 76 having guiding fins 77 and 78 adapted to extend beneath segmental retaining plates 7 9 and 80 bolted to the block 71, and arranged to clamp the posts 75 and 7 6 in any relative angular position to which they may be adjusted. The outer ends of the posts 7 5 and 76 are pro'- vided with guideways 81 and 82 for the slidable reception "of the shanks of the truing devices 83 and 84, the post 75 bein somewhat longer than the post 76 so that the truing devices move in non-intersecting paths in substantially parallel planes, one immediately back of the other and substantially diametrically of the gyrostati-c wheel as shown in Fig. 4. Each truing device may be reciprocated by means of a hand lever 85, 86 fast to shafts 87 and 88 which have pinions such as 89 thereon meshing with rack portions on their respective truing device shanks. A third truing device shown at 90 may be employed to remove the extreme edge of apex of the grinding ring 11 at 91 to conform to the shape of U. S. standard thread.

Operation: The Work to be ground is placed in position adjacent the edge of the grinding wheel between centers in the usual manner, and the wheel is adjusted by sliding the block B on the frame A as desired, angular adjustment of the wheel being also effected by manipulation of the turn buckle 3. On imparting rotation to the shaft E, rotation of shafts 25 and 26 in the same direction is produced by the action oftheir respective transmission belts, which are urged into operative condition by their respective and independent belt tightening mechanisms. Motion is transmitted through the flexible shock absorbing couplings 29 and 30, and the jawed couplings, to both ends of the wheel shaft 8. The jawed couplings transmit almost entirely rotational motion, their construction allowing considerable freedom of relative axial motion of the drive and driven shafts. The work is fed to the wheel by any suitable or usual mechanism, this forming no part of the present invention.

Abrasive wheels as commercially made contain relatively hard and soft spots causing the load on the wheel from impact with the work to fluctuate both laterally and longitudinally of the grinding edge, the lateral fluctuations tending to displace the edge laterally and the longitudinal fluctuations tending to produce variations in the speed of the wheel. The nature of the work often adds to these disturbing factors, the longitudinal flutings in taps for example, acting to produce sudden and extreme variations in load. The momentum of the heavy wheel here used, acts to prevent the changes in speed, while its gyrostatic action, forcibly resisting any change in its plane of rotation, causes the wheel to run true laterally. The construction and arrangement of parts as above described has been found in practice to make possible production of a high quality.

When it is desired to true the wheel edge, this: may be accomplished in an easy expeditious manner, by traversing the truing devices 83, 8 1, and 90 which are preferably of the diamond type, across the cutting faces of the wheel by manipulation of their respective handles as and 86, angular adjustment of tools 83 and 84 being effected by turning the posts 7 5 and 7 (5 on the pivot 74, and movement to and from the Wheel by manipulation of the knurled head 73. It should be noted that pivot 74:, during the movements of block 71, remains in the central plane of the grinding ring 11 so that the apex of the intersecting side grinding faces of the ring is maintained centrally thereof and that the truing is effected while the wheel is in operative position for grindmg.

When it is desired to remove the grinding wheel from the machine, the bolts 55 and 56 are released and swung outwardly and downwardly, and the upper portion of the wheel. casing carrying the truing devices 83 and s4 is tiltedupwardly and rearwardly about the pivot 51. The jawed couplin s at the ends of shafts 8 may be released by loosening screws 31 32. Hooks of a hoisting device may be inserted in openings 23 in the discs 23 and the grinding wheel with its shaft and parts carried thereby may be lifted from the blocks 5 and 6. As a stream of water Or other cooling fluid is commonly directed on the cutting portion of the wheel during the operation of the machine, discs 23 function at that time as guards to prevent entry of such fluid as well as abrasive or other particles to the bearings.

Having thus described one embodiment of this invention as merely illustrative thereof, it will be evident that many changes might be made therein without departing from itssp-irit or scope as defined by the following claims: 7

1. In a grinding machine, a grinding wheel, a support adjacent thereto, a slide carried by said support and adjustable thereon toward and from the cutting portion of said wheel, a pair of posts pivoted at one end to said slide, and angularly adjustable thereon, slideways at the opposite ends of said posts, a truing tool slidably mounted in each of said slideways, said tools being movable in non-intersecting paths and independent manually actuated means for moving said tools in said slideways across the cutting portion of said wheel.

2. In a grinding machine, a grinding wheel, a casing ifcr said Wheel a bracket extending from said casingand having a slideway therein, a block adjustable longi-' tudinally in, said slideway, a pair of posts pivoted to said block on a common pivot, one OfSZllClPOStS'bQlHg longer than theother, anda wheel truing device movably earned HARRY E. HARRIS.

'ture. 

